diff --git a/replication/log.go b/ledis/binlog.go
similarity index 64%
rename from replication/log.go
rename to ledis/binlog.go
index 4cdc460..c5df748 100644
--- a/replication/log.go
+++ b/ledis/binlog.go
@@ -1,8 +1,9 @@
-package replication
+package ledis
 
 import (
 	"bufio"
-	"errors"
+	"encoding/binary"
+	"encoding/json"
 	"fmt"
 	"github.com/siddontang/go-log/log"
 	"io/ioutil"
@@ -10,27 +11,56 @@ import (
 	"path"
 	"strconv"
 	"strings"
+	"time"
 )
 
-var (
-	ErrOverSpaceLimit = errors.New("total log files exceed space limit")
+const (
+	MaxBinLogFileSize int = 1024 * 1024 * 1024
+	MaxBinLogFileNum  int = 10000
+
+	DefaultBinLogFileSize int = MaxBinLogFileSize
+	DefaultBinLogFileNum  int = 10
 )
 
-type logHandler interface {
-	Write(wb *bufio.Writer, data []byte) (int, error)
-}
+/*
+index file format:
+ledis-bin.00001
+ledis-bin.00002
+ledis-bin.00003
 
-type LogConfig struct {
+log file format
+
+timestamp(bigendian uint32, seconds)|PayloadLen(bigendian uint32)|PayloadData
+
+*/
+
+type BinLogConfig struct {
 	Name        string `json:"name"`
-	LogType     string `json:"log_type"`
 	Path        string `json:"path"`
 	MaxFileSize int    `json:"max_file_size"`
 	MaxFileNum  int    `json:"max_file_num"`
-	SpaceLimit  int64  `json:"space_limit"`
 }
 
-type Log struct {
-	cfg *LogConfig
+func (cfg *BinLogConfig) adjust() {
+	if cfg.MaxFileSize <= 0 {
+		cfg.MaxFileSize = DefaultBinLogFileSize
+	} else if cfg.MaxFileSize > MaxBinLogFileSize {
+		cfg.MaxFileSize = MaxBinLogFileSize
+	}
+
+	if cfg.MaxFileNum <= 0 {
+		cfg.MaxFileNum = DefaultBinLogFileNum
+	} else if cfg.MaxFileNum > MaxBinLogFileNum {
+		cfg.MaxFileNum = MaxBinLogFileNum
+	}
+
+	if len(cfg.Name) == 0 {
+		cfg.Name = "ledis"
+	}
+}
+
+type BinLog struct {
+	cfg *BinLogConfig
 
 	logFile *os.File
 
@@ -39,28 +69,30 @@ type Log struct {
 	indexName    string
 	logNames     []string
 	lastLogIndex int
-
-	space int64
-
-	handler logHandler
 }
 
-func newLog(handler logHandler, cfg *LogConfig) (*Log, error) {
-	l := new(Log)
+func NewBinLog(data json.RawMessage) (*BinLog, error) {
+	var cfg BinLogConfig
+
+	if err := json.Unmarshal(data, &cfg); err != nil {
+		return nil, err
+	}
+
+	return NewBinLogWithConfig(&cfg)
+}
+
+func NewBinLogWithConfig(cfg *BinLogConfig) (*BinLog, error) {
+	cfg.adjust()
+
+	l := new(BinLog)
 
 	l.cfg = cfg
-	l.handler = handler
-
-	if len(l.cfg.Name) == 0 {
-		l.cfg.Name = "ledis"
-	}
 
 	if err := os.MkdirAll(cfg.Path, os.ModePerm); err != nil {
 		return nil, err
 	}
 
 	l.logNames = make([]string, 0, 16)
-	l.space = 0
 
 	if err := l.loadIndex(); err != nil {
 		return nil, err
@@ -69,7 +101,7 @@ func newLog(handler logHandler, cfg *LogConfig) (*Log, error) {
 	return l, nil
 }
 
-func (l *Log) flushIndex() error {
+func (l *BinLog) flushIndex() error {
 	data := strings.Join(l.logNames, "\n")
 
 	bakName := fmt.Sprintf("%s.bak", l.indexName)
@@ -95,8 +127,8 @@ func (l *Log) flushIndex() error {
 	return nil
 }
 
-func (l *Log) loadIndex() error {
-	l.indexName = path.Join(l.cfg.Path, fmt.Sprintf("%s-%s.index", l.cfg.Name, l.cfg.LogType))
+func (l *BinLog) loadIndex() error {
+	l.indexName = path.Join(l.cfg.Path, fmt.Sprintf("%s-bin.index", l.cfg.Name))
 	if _, err := os.Stat(l.indexName); os.IsNotExist(err) {
 		//no index file, nothing to do
 	} else {
@@ -112,12 +144,10 @@ func (l *Log) loadIndex() error {
 				continue
 			}
 
-			if st, err := os.Stat(path.Join(l.cfg.Path, line)); err != nil {
+			if _, err := os.Stat(path.Join(l.cfg.Path, line)); err != nil {
 				log.Error("load index line %s error %s", line, err.Error())
 				return err
 			} else {
-				l.space += st.Size()
-
 				l.logNames = append(l.logNames, line)
 			}
 		}
@@ -147,11 +177,11 @@ func (l *Log) loadIndex() error {
 	return nil
 }
 
-func (l *Log) getLogFile() string {
-	return fmt.Sprintf("%s-%s.%07d", l.cfg.Name, l.cfg.LogType, l.lastLogIndex)
+func (l *BinLog) getLogFile() string {
+	return fmt.Sprintf("%s-bin.%07d", l.cfg.Name, l.lastLogIndex)
 }
 
-func (l *Log) openNewLogFile() error {
+func (l *BinLog) openNewLogFile() error {
 	var err error
 	lastName := l.getLogFile()
 
@@ -180,7 +210,7 @@ func (l *Log) openNewLogFile() error {
 	return nil
 }
 
-func (l *Log) checkLogFileSize() bool {
+func (l *BinLog) checkLogFileSize() bool {
 	if l.logFile == nil {
 		return false
 	}
@@ -197,15 +227,9 @@ func (l *Log) checkLogFileSize() bool {
 	return false
 }
 
-func (l *Log) purge(n int) {
+func (l *BinLog) purge(n int) {
 	for i := 0; i < n; i++ {
 		logPath := path.Join(l.cfg.Path, l.logNames[i])
-		if st, err := os.Stat(logPath); err != nil {
-			log.Error("purge %s error %s", logPath, err.Error())
-		} else {
-			l.space -= st.Size()
-		}
-
 		os.Remove(logPath)
 	}
 
@@ -213,22 +237,22 @@ func (l *Log) purge(n int) {
 	l.logNames = l.logNames[0 : len(l.logNames)-n]
 }
 
-func (l *Log) Close() {
+func (l *BinLog) Close() {
 	if l.logFile != nil {
 		l.logFile.Close()
 		l.logFile = nil
 	}
 }
 
-func (l *Log) LogNames() []string {
+func (l *BinLog) LogNames() []string {
 	return l.logNames
 }
 
-func (l *Log) LogFileName() string {
+func (l *BinLog) LogFileName() string {
 	return l.getLogFile()
 }
 
-func (l *Log) LogFilePos() int64 {
+func (l *BinLog) LogFilePos() int64 {
 	if l.logFile == nil {
 		return 0
 	} else {
@@ -237,7 +261,7 @@ func (l *Log) LogFilePos() int64 {
 	}
 }
 
-func (l *Log) Purge(n int) error {
+func (l *BinLog) Purge(n int) error {
 	if len(l.logNames) == 0 {
 		return nil
 	}
@@ -255,11 +279,7 @@ func (l *Log) Purge(n int) error {
 	return l.flushIndex()
 }
 
-func (l *Log) Log(args ...[]byte) error {
-	if l.cfg.SpaceLimit > 0 && l.space >= l.cfg.SpaceLimit {
-		return ErrOverSpaceLimit
-	}
-
+func (l *BinLog) Log(args ...[]byte) error {
 	var err error
 
 	if l.logFile == nil {
@@ -268,17 +288,23 @@ func (l *Log) Log(args ...[]byte) error {
 		}
 	}
 
-	totalSize := 0
+	//we treat log many args as a batch, so use same createTime
+	createTime := uint32(time.Now().Unix())
 
-	var n int = 0
 	for _, data := range args {
-		if n, err = l.handler.Write(l.logWb, data); err != nil {
-			log.Error("write log error %s", err.Error())
+		payLoadLen := uint32(len(data))
+
+		if err := binary.Write(l.logWb, binary.BigEndian, createTime); err != nil {
 			return err
-		} else {
-			totalSize += n
 		}
 
+		if err := binary.Write(l.logWb, binary.BigEndian, payLoadLen); err != nil {
+			return err
+		}
+
+		if _, err := l.logWb.Write(data); err != nil {
+			return err
+		}
 	}
 
 	if err = l.logWb.Flush(); err != nil {
@@ -286,8 +312,6 @@ func (l *Log) Log(args ...[]byte) error {
 		return err
 	}
 
-	l.space += int64(totalSize)
-
 	l.checkLogFileSize()
 
 	return nil
diff --git a/replication/binlog_test.go b/ledis/binlog_test.go
similarity index 96%
rename from replication/binlog_test.go
rename to ledis/binlog_test.go
index 48263ae..995a8d1 100644
--- a/replication/binlog_test.go
+++ b/ledis/binlog_test.go
@@ -1,4 +1,4 @@
-package replication
+package ledis
 
 import (
 	"io/ioutil"
diff --git a/ledis/ledis.go b/ledis/ledis.go
index d9425b5..0cf108a 100644
--- a/ledis/ledis.go
+++ b/ledis/ledis.go
@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"github.com/siddontang/go-leveldb/leveldb"
-	"github.com/siddontang/ledisdb/replication"
 	"path"
 	"sync"
 )
@@ -18,7 +17,7 @@ type Config struct {
 	UseBinLog bool `json:"use_bin_log"`
 
 	//if you not set bin log path, use data_dir/bin_log
-	BinLog replication.BinLogConfig `json:"bin_log"`
+	BinLog BinLogConfig `json:"bin_log"`
 }
 
 type DB struct {
@@ -42,7 +41,7 @@ type Ledis struct {
 	ldb *leveldb.DB
 	dbs [MaxDBNumber]*DB
 
-	binlog *replication.Log
+	binlog *BinLog
 
 	quit chan struct{}
 }
@@ -81,7 +80,7 @@ func OpenWithConfig(cfg *Config) (*Ledis, error) {
 		if len(cfg.BinLog.Path) == 0 {
 			cfg.BinLog.Path = path.Join(cfg.DataDir, "bin_log")
 		}
-		l.binlog, err = replication.NewBinLogWithConfig(&cfg.BinLog)
+		l.binlog, err = NewBinLogWithConfig(&cfg.BinLog)
 		if err != nil {
 			return nil, err
 		}
diff --git a/ledis/replication.go b/ledis/replication.go
index 8de0bc9..9a2cb1b 100644
--- a/ledis/replication.go
+++ b/ledis/replication.go
@@ -14,7 +14,7 @@ var (
 	errInvalidBinLogEvent = errors.New("invalid binglog event")
 )
 
-func (l *Ledis) replicateEvent(event []byte) error {
+func (l *Ledis) ReplicateEvent(event []byte) error {
 	if len(event) == 0 {
 		return errInvalidBinLogEvent
 	}
@@ -70,8 +70,8 @@ func (l *Ledis) replicateCommandEvent(event []byte) error {
 	return errors.New("command event not supported now")
 }
 
-func (l *Ledis) RepliateRelayLog(relayLog string, offset int64) (int64, error) {
-	f, err := os.Open(relayLog)
+func (l *Ledis) RepliateFromBinLog(filePath string, offset int64) (int64, error) {
+	f, err := os.Open(filePath)
 	if err != nil {
 		return 0, err
 	}
@@ -114,7 +114,7 @@ func (l *Ledis) RepliateRelayLog(relayLog string, offset int64) (int64, error) {
 			}
 
 			l.Lock()
-			err = l.replicateEvent(dataBuf.Bytes())
+			err = l.ReplicateEvent(dataBuf.Bytes())
 			l.Unlock()
 			if err != nil {
 				log.Fatal("replication error %s, skip to next", err.Error())
diff --git a/ledis/replication_test.go b/ledis/replication_test.go
index 2fc02a4..2e4b977 100644
--- a/ledis/replication_test.go
+++ b/ledis/replication_test.go
@@ -38,14 +38,14 @@ func TestReplication(t *testing.T) {
 	db.Set([]byte("b"), []byte("2"))
 	db.Set([]byte("c"), []byte("3"))
 
-	relayLog := "/tmp/test_repl/master/bin_log/ledis-bin.0000001"
+	binLogName := "/tmp/test_repl/master/bin_log/ledis-bin.0000001"
 
 	var offset int64
-	offset, err = slave.RepliateRelayLog(relayLog, 0)
+	offset, err = slave.RepliateFromBinLog(binLogName, 0)
 	if err != nil {
 		t.Fatal(err)
 	} else {
-		if st, err := os.Stat(relayLog); err != nil {
+		if st, err := os.Stat(binLogName); err != nil {
 			t.Fatal(err)
 		} else if st.Size() != offset {
 			t.Fatal(st.Size(), offset)
diff --git a/ledis/tx.go b/ledis/tx.go
index 6c4c023..fa7379b 100644
--- a/ledis/tx.go
+++ b/ledis/tx.go
@@ -2,7 +2,6 @@ package ledis
 
 import (
 	"github.com/siddontang/go-leveldb/leveldb"
-	"github.com/siddontang/ledisdb/replication"
 	"sync"
 )
 
@@ -12,7 +11,7 @@ type tx struct {
 	l  *Ledis
 	wb *leveldb.WriteBatch
 
-	binlog *replication.Log
+	binlog *BinLog
 	batch  [][]byte
 }
 
diff --git a/replication/binlog.go b/replication/binlog.go
deleted file mode 100644
index ad9163c..0000000
--- a/replication/binlog.go
+++ /dev/null
@@ -1,89 +0,0 @@
-package replication
-
-import (
-	"bufio"
-	"encoding/binary"
-	"encoding/json"
-	"time"
-)
-
-const (
-	MaxBinLogFileSize int = 1024 * 1024 * 1024
-	MaxBinLogFileNum  int = 10000
-
-	DefaultBinLogFileSize int = MaxBinLogFileSize
-	DefaultBinLogFileNum  int = 10
-)
-
-/*
-index file format:
-ledis-bin.00001
-ledis-bin.00002
-ledis-bin.00003
-
-log file format
-
-timestamp(bigendian uint32, seconds)|PayloadLen(bigendian uint32)|PayloadData
-
-*/
-
-type BinLogConfig struct {
-	LogConfig
-}
-
-func (cfg *BinLogConfig) adjust() {
-	if cfg.MaxFileSize <= 0 {
-		cfg.MaxFileSize = DefaultBinLogFileSize
-	} else if cfg.MaxFileSize > MaxBinLogFileSize {
-		cfg.MaxFileSize = MaxBinLogFileSize
-	}
-
-	if cfg.MaxFileNum <= 0 {
-		cfg.MaxFileNum = DefaultBinLogFileNum
-	} else if cfg.MaxFileNum > MaxBinLogFileNum {
-		cfg.MaxFileNum = MaxBinLogFileNum
-	}
-
-	//binlog not care space limit
-	cfg.SpaceLimit = -1
-
-	cfg.LogType = "bin"
-}
-
-type binlogHandler struct {
-}
-
-func (h *binlogHandler) Write(wb *bufio.Writer, data []byte) (int, error) {
-	createTime := uint32(time.Now().Unix())
-	payLoadLen := uint32(len(data))
-
-	if err := binary.Write(wb, binary.BigEndian, createTime); err != nil {
-		return 0, err
-	}
-
-	if err := binary.Write(wb, binary.BigEndian, payLoadLen); err != nil {
-		return 0, err
-	}
-
-	if _, err := wb.Write(data); err != nil {
-		return 0, err
-	}
-
-	return 8 + len(data), nil
-}
-
-func NewBinLog(data json.RawMessage) (*Log, error) {
-	var cfg BinLogConfig
-
-	if err := json.Unmarshal(data, &cfg); err != nil {
-		return nil, err
-	}
-
-	return NewBinLogWithConfig(&cfg)
-}
-
-func NewBinLogWithConfig(cfg *BinLogConfig) (*Log, error) {
-	cfg.adjust()
-
-	return newLog(new(binlogHandler), &cfg.LogConfig)
-}
diff --git a/replication/relaylog.go b/replication/relaylog.go
deleted file mode 100644
index 4ee2a4a..0000000
--- a/replication/relaylog.go
+++ /dev/null
@@ -1,50 +0,0 @@
-package replication
-
-import (
-	"bufio"
-	"encoding/json"
-)
-
-const (
-	MaxRelayLogFileSize     int = 1024 * 1024 * 1024
-	DefaultRelayLogFileSize int = MaxRelayLogFileSize
-)
-
-type RelayLogConfig struct {
-	LogConfig
-}
-
-func (cfg *RelayLogConfig) adjust() {
-	if cfg.MaxFileSize <= 0 {
-		cfg.MaxFileSize = DefaultRelayLogFileSize
-	} else if cfg.MaxFileSize > MaxRelayLogFileSize {
-		cfg.MaxFileSize = MaxRelayLogFileSize
-	}
-
-	//relaylog not care file num
-	cfg.MaxFileNum = -1
-	cfg.LogType = "relay"
-}
-
-type relayLogHandler struct {
-}
-
-func (h *relayLogHandler) Write(wb *bufio.Writer, data []byte) (int, error) {
-	return wb.Write(data)
-}
-
-func NewRelayLog(data json.RawMessage) (*Log, error) {
-	var cfg RelayLogConfig
-
-	if err := json.Unmarshal(data, &cfg); err != nil {
-		return nil, err
-	}
-
-	return NewRelayLogWithConfig(&cfg)
-}
-
-func NewRelayLogWithConfig(cfg *RelayLogConfig) (*Log, error) {
-	cfg.adjust()
-
-	return newLog(new(relayLogHandler), &cfg.LogConfig)
-}
diff --git a/replication/relaylog_test.go b/replication/relaylog_test.go
deleted file mode 100644
index 0cde67b..0000000
--- a/replication/relaylog_test.go
+++ /dev/null
@@ -1,41 +0,0 @@
-package replication
-
-import (
-	"os"
-	"testing"
-)
-
-func TestRelayLog(t *testing.T) {
-	cfg := new(RelayLogConfig)
-
-	cfg.MaxFileSize = 1024
-	cfg.SpaceLimit = 1024
-	cfg.Path = "/tmp/ledis_relaylog"
-	cfg.Name = "ledis"
-
-	os.RemoveAll(cfg.Path)
-
-	b, err := NewRelayLogWithConfig(cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if err := b.Log(make([]byte, 1024)); err != nil {
-		t.Fatal(err)
-	}
-
-	if err := b.Log(make([]byte, 1)); err == nil {
-		t.Fatal("must not nil")
-	} else if err != ErrOverSpaceLimit {
-		t.Fatal(err)
-	}
-
-	if err := b.Purge(1); err != nil {
-		t.Fatal(err)
-	}
-
-	if err := b.Log(make([]byte, 1)); err != nil {
-		t.Fatal(err)
-	}
-
-}
diff --git a/server/app.go b/server/app.go
index e293a14..cf76049 100644
--- a/server/app.go
+++ b/server/app.go
@@ -3,7 +3,6 @@ package server
 import (
 	"fmt"
 	"github.com/siddontang/ledisdb/ledis"
-	"github.com/siddontang/ledisdb/replication"
 	"net"
 	"strings"
 )
@@ -19,8 +18,6 @@ type App struct {
 
 	slaveMode bool
 
-	relayLog *replication.Log
-
 	quit chan struct{}
 }
 
@@ -57,10 +54,6 @@ func NewApp(cfg *Config) (*App, error) {
 
 	if len(app.cfg.SlaveOf) > 0 {
 		app.slaveMode = true
-
-		if app.relayLog, err = replication.NewRelayLogWithConfig(&cfg.RelayLog); err != nil {
-			return nil, err
-		}
 	}
 
 	if app.ldb, err = ledis.OpenWithConfig(&cfg.DB); err != nil {
diff --git a/server/config.go b/server/config.go
index 518a083..80214c3 100644
--- a/server/config.go
+++ b/server/config.go
@@ -3,7 +3,6 @@ package server
 import (
 	"encoding/json"
 	"github.com/siddontang/ledisdb/ledis"
-	"github.com/siddontang/ledisdb/replication"
 	"io/ioutil"
 )
 
@@ -18,9 +17,6 @@ type Config struct {
 	//set slaveof to enable replication from master
 	//empty, no replication
 	SlaveOf string `json:"slaveof"`
-
-	//if you not set relay log path, use data_dir/realy_log
-	RelayLog replication.RelayLogConfig `json:"relay_log"`
 }
 
 func NewConfig(data json.RawMessage) (*Config, error) {